Fixture for use in metal working operations



Jan. 28, 1958 P. 1.. DUGAS ETAL FIXTURE FOR USE IN METAL WORKING OPERATIONS e sheets-sheet 1 Filed March 25, 1957 Jan. 28, 1958 P. L. DUGAS EI'AL 7 FIXTURE FOR USE IN METAL-WORKING OPERATIONS Filed March 25, 1957 6 Sheets-Sheet 2 INVENTORS.

Jan. 28, 1958 P. DUGAS ETAL k FIXTURE FOR USE IN METAL WORKING OPERATIONS Filed March 25, 1957 6 Shets-Sheet 3 INVENTORS.

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FIXTURE FOR USE IN METAL WORKING OPERATIONS I Filed March 25, 1957 6' Sheets-Sheet 4 INVENTOR-st I FIVE/g Jan. 28, 1958 P. 1.. DUGAS ET AL FIXTURE FOR USE IN METAL WORKING OPERATIONS 6 Sheets-Sheet 5 Filed March 25, 1957 Z; x m PM 3 RM my By I fa/$72 M QC/Es} Jan. 28, 1958 P. L. DUGAS ET AL FIXTURE FOR USE IN METAL WORKING OPERATIONS 6 Sheets-Sheet 6 Filed March 25, 1957 as 2477 M Jae/k INVENTORS. 2%? A Ja J5 BY Unite FIXTURE FOR USE lhl METAL WORKIN G OPERATIONS Paul L. Dugas, Berkley, and John M. Jacksy, Detroit,

Mich, assignors to Colonial Brunch and Machine Company, Detroit, Mich, a corporation of Delaware Application March 25, 1957, Serial No. 648,380

8 Claims. (Cl. 90-43) An important object of the invention is to provide an improved work-holding fixture which permits the manufacture of finished workpieces requiring multiple and diversified metal working operations on an automatic production basis.

Another important object of the invention is to'provide an improved work-holding fixture which effects economies in the production of like workpieces and wherein a plurality of such workpieces may be maintained in predetermined positions while being transported through work-performing stations and while metal working operations are performed thereon.

Still other important objects of the invention are: to provide an improved work-holding fixture wherein the means for carrying a plurality of workpieces in predetermined positions clamps against portions of the workpieces while maintaining other portions accessible to work tools whereby variant metal finishing operations may be performed on the workpieces simultaneously and successively; to provide an improved work-holding fixture which is quickly and easily adaptable to support work pieces of different sizes, which commonly clamps a plurality of workpieces of a given size and compensates for dimensional variations therein, and which requires but a single adjustment for clamping or releasing all of the workpieces therein.

Still another important object of the invention is to provide an improved work-holding fixture for elongated workpieces which includes means for supporting such workpieces at their ends, the supporting means for the ends to be finished including pairs of clamping jaws of which certain ones are movable relative to others and which includes means for commonly actuating all of the movable jaws so that they seat firmly and uniformly against the workpiece ends to be finished.

The above and related objects will appear more fully during the course of the following description taken in conjunction with the accompanying drawings.

in the drawings:

Fig. l is a front elevational view of a workholding fixture embodying the invention with typical workparts clamped in place;

Fig. 2 is a plan view of the structure of Fig. 1;

Figs. 3 and 4 are vertical sectional views of the structure of Fig. 1 taken respectively along the lines 3-3 and l4 thereof;

Figs. 5 and 6 are horizontal sectional views of the structure of Fig. 1 taken respectively along the lines 5-5 and 6-6 thereof;

Fig. 7 is a side elevational view of one of the workpieces shown in Fig. 1; and

Fig. 8 is a right side elevational view of the structure of Fig. 7.

The work-holding fixture of the present invention is embodied in a device for clamping elongated workpieces while metal working operations are performed thereon to produce finished pieces. he particular embodiment of work-holding fixture shown and to be described is of a type fer clamping forged wrench parts such as the one shown by way of illustration in finished form in Figs. 7 and 8 and indicated generally at 11. The wrench part 11 constitutes the principal part of a commonly used and well known type of adjustable wrench and comprises a handle portion 13 provided with an opening 14 adjacent one end thereof and head 15 adjacent the opposite end thereof. The forged head 15 of each wrench part must be subjected to diversified metal working or machining operations before it can accommodate a movable jaw and related parts (not shown) to make up a completed and usable wrench.

Various cooperating internal openings and external structure of the head 15 and the manner in which they are formed will be briefly mentioned to illustrate the nature of the divers machining operations that must be performed in finishing the wrench part 11. The head 15 is provided with a stationary jaw 17 which stands upright from the floor 19 of the head and the adjacent faces of the jaw 17 and the fioor 19 are broached as well as the face of the angled portion 21 joining the jaw and the floor. Extending horizontally through the floor 19 and the jaw 17' is an open-ended slideway indicated generally at 23 for slidably carrying the movable jaw of the wrench. The lower arcuate portion 23A of the slideway is drilled and reamed while the upper rectangular portion 233 is broached, and it should be noted with respect to the latter portion that it is open at its top along the floor 19 while within the jaw 17 it has a top surface which is angled downwardly and to the left as indicated at 24 in Fig. 7.

Communicating with the bottom of the slideway 23 and extending transversely through the head 15 is a rectangular worm opening 25 which is also broached at least on its top surface and which accommodates an actuating worm wheel (not shown) for the movable jaw. For rotatably supporting the worm wheel an aperture 27 is drilled beneath and parallel to the slideway 23 through the metal on both sides of the worm opening 25. The shortest section of the aperture 27 on the right side of the worm opening 25 as viewed in Fig. 7 is tapped. The ends of the slideway 223 and aperture 27 on the jaw side of the head are end milled. The opposite side surfaces 28 of the head from its tip to just below the top of the worm opening 25 are each broached on a taper and as can be seen from Fig. 8 the side surfaces 28 converge toward the tip of the head 15. The above enumerated metal working operations and others which are required to produce the finished wrench part 11 form a considerable portion of the cost of finished wrenches and heretofore have been performed for the most part by means which necessitated separate handling of the wrench parts through the required work-performing stations on a production line and different handling at each station.

By provision of the work handling fixture of the present invention a plurality of substantially like workpieces may be clamped as a unit and commonly carried in proper positional relationship with respect to the required broaching, drilling, reaming, tapping and milling tools which may operate separately, simultaneously or sequentially at one or more work-performing stations.

Referring now in greater detail to the drawings and commencing with Fig. 1 the work handling fixture of the invention comprises stationary structure which includes a metal. base indicated generally at 31. The base 31 is suite able for mounting on a pallet or the like (not shown) which in turn is adapted to be transported on a conveyor through the required tool stations. integrally formed with the base 31 are upright end posts 33L and 33R and an upright center post 35. Stationary end jaws 37L and 37R are fixedly secured to the top of the end posts 33L and 33R and a stationary center jaw 38 is similarly secured to the top of the center post 35. Positioned between and spaced from the stationary end jaws 37L and 37R are a pair of movable jaws 41L and 41R and the stationary center jaw 38 is disposed between and spaced from the movable jaws 41L and 41R. The opposed faces of each adjacent pair of jaws are tapered relatively so that they converge toward the top of the fixture. From front to back of the fixture, as can be seen from the plan view of Fig. 2, the opposed faces of each adjacent pair of jaws conform to the opposite side surfaces 28 of the head of the wrench part 11.

The movable jaws 41L and 41R are secured to jaw support members 47L and 47R from which depend integrally formed vertical rods 49L and 49R as best shown for the jaw 41L and rod 49L in Fig. 3. The support members 47L and 47R extend vertically behind the jaws 41L and 41R and are inturned toward the front of the fixture to engage recesses 46L and 46R formed in the top and at the rear of the jaws 41L and 41R as can be seen by reference to Figs. l-3. The jaws 41L and 41R are removably se cured to support members 47L and 47R by suitable means as by the fastener 48 and related parts shown in Fig. 3 for the jaw 41L so that they may be quickly replaced when necessary by difierent size jaws to accommodate different sizes of workpieces. The rods 49L and 49R are loosely carried for sliding movement in vertical guide openings 51L and 51R formed in the base 31 and for this purpose bushings such as the one shown and indicated at 52 in Fig. 3 are fitted in the openings 51L and 51R. The internal diameter of each bushing 52 is somewhat larger than the diameter of each of the rods 49L and 49R to permit some lateral float or play of each rod in its respective bushing. Thus the movable jaws 41L and 41R are able to tilt about a horizontal plane but are prevented from rotating about the axes of the rods 49L and 49R by set screws as at 53 (Fig. 3), the inner ends of which extend into vertical keyways 54 formed in the rods 49L and 49R.

Abutments 54L and 54R protrude outwardly from the upper portions of the base 31 as shown in Figs. 1 and 3 so as to support L-shaped members SSL and 55R provided with integral upright broach guides 56L and 56R which are disposed below and in front of the movable jaws 41L and 41R and which will be referred to later.

All of the fixture jaws are spaced from each other as previously mentioned and in the space between each adjacent pair of jaws one end of an elongated workpiece is adapted to be clamped as shown for the head of each wrench part 11 in Figs. 1 and 2. The wrench parts 11 are arranged in spaced pairs on opposite sides of the center post 35. Thus the heads of the lefthand pair of wrench parts are clamped by seating of the movable jaw 41L between the end jaw 37L and the center jaw 38. Similarly the heads of the righthand pair of wrench parts are clamped by seating of the movable jaw 41R between the end jaw 37R and the center jaw 38. As the movable jaws 41L and 41R are drawn downwardly the amount of relative convergence between the opposed faces of each adjacent pair of jaws increases to securely clamp or wedge the head of the respective wrench part.

The lower ends of the wrench parts are pivotally supported by way of their openings 14 on pins 59 which are secured in the end posts 33L and 33R and in the center post 35 by set screws 61 as shown in Figs. 1, 3 and 5. The pins 59 are disposed in bushings in openings 63 which extend inwardly from opposite sides of the center post 35 and from the inner side of each. of the end sides. The openings 63'on each post side are disposed in vertically spaced relationship to each other. The corresponding pin 59 may be interchangeably positioned in any one of the openings 63 on its respective post side to accommodate difierent wrench part sizes. In the particular embodiment being described the pins 59 are disposed in the lowermost openings 63 to provide the greatest distance from the fixture jaws so as to accommodate the largest size wrench parts.

The wrench parts when secured as described tilt backwardly and upwardly to the fixture jaws and the headof each wrench part is positioned between each adjacent pair of fixture jaws substantially as shown for the particular wrench part in Fig. 3 which is the one clamped between the movable jaw 41L and the stationary center jaw 38. It can be seen that the floor 19, the jaw 17 and the adjoining angled portion 21 of the said wrench part are arranged so that their faces protrude from the similarly shaped frontal surfaces of the movable jaw 41L and are therefore accessible by various machine tools. It should be noted with respect to the frontal surfaces of the movable jaw 41L that the floor portion thereof which is indicated at 65 is relatively fiat and disposed essentially in one plane as is the corresponding floor portion of the other movable jaw 41R. The frontal surfaces of the movable jaws should be compared with the frontal surfaces of the stationary jaw 38 a central vertical cross-section of which can be seen from reference to Fig. 4. The corresponding floor portion of the center jaw 38 has a front section indicated at 66 and an intermediate section 67. The front section 66 extends upwardly to the same height as the floor portions 65 of the movable jaws. The section 67 drops below the section 66 so as to lie in a plane just above the plane of the lower surfaces of the worm openings 25 in the wrench parts 11. The section 67 of the center jaw floor portion is so disposed to support the broaching tool which broaches desired surfaces of the worm opening 25 as will appear more fully hereinafter; For this purpose a short upright rib 68 is formed as shown in Fig. 4 as a part of the floor portion of the center jaw 38 and serves as a broach guide for the last-mentioned broaching tool. The stationary end jaws 37L and 37R are not shown in crosssection as are at least one of each of the other type fixture jaws but it may be noted from the plan view of Fig. 2 that their frontal surfaces are similar to those of the center jaw 38 and include corresponding floor portions which have front sections 69L and 69R and intermediate sections 70L and 70R. The stationary end jaws 37L and 37R are also provided with short upright ribs 71L and 71R which are formed as a part of their floor portions and serve as broach guides. The front sections 69L and 69R and the intermediate sections 70L and 70R of the end jaw fioor portions are disposed in the same plane and for the same purposes as the corresponding sections 66 and 67 respectively of the center jaw floor portion. Thus the floor portions of the pair of movable jaws and the forward sections of the floor portions of the stationary jaws collectively define a broaching floor over which a suitable broaching tool may be guided and travel from opposite sides of the base 31 toward the center and return for simultaneously broaching the faces of each jaw 17, floor 19 and angled portion 21 of the wrench parts 11.

In the position in which the wrench parts are clamped between adjacent pairs of fixture jaws the other portions of the heads of the wrench parts which must be machined are accessible to the various tools that are required. Thus the slideways 23 of the wrench parts may be drilled and reamed and broached as previously mentioned by tools which pass transversely of the base 31 into the metal of the heads as they are clamped between adjacent pairs of fixture jaws. Similarly the apertures 27 in the wrench parts may be drilled and tapped at suitable stations while they are secured in the fixture as shown. Provision is made for broaching the rectangular worm openings 25 in the wrench parts in succession while they are clamped in place on the fixture and to accomplish this the required tool must pass longitudinally of the base over the pair of stationary end jaws and the center jaw and below the pair of movable jaws at the proper position with relation to the head of each wrench part. For this purpose an access opening is provided below each of the pair of movable jaws so as to extend longitudinally thereof from end to end. As shown in the cross-sectional view of Fig. 3 for the movable jaw 41L each access opening is defined by the space between the floor portion 65 of each movable jaw and its respective one of the L-shaped members SSL and 55R on which the broach guides 56L and 56R are formed. Each access opening is aligned with the worm openings 25 in the wrench parts 11. As shown most clearly in the longitudinal sectional view of Fig. 6 the intermediate sections of the floor portions of the stationary jaws collectively define with the L-shaped members SSL and 55R a floor over which a suitable broaching tool may pass for broaching the top and side surfaces of the worm openings 25 and the wrench parts 11. The floor extends longitudinally from one end to the other of the fixture through the access openings below the pair of movable jaws 41L and 41R and as the broaching tool moves thereover it is guided by the broach guides 71L and 71R, 56L and 56R and 68 which are axially aligned as shown in Fig. 6. The broaching tool for the worm openings may make several passes at one or more tool stations through which the fixture is carried until the worm opening in the head of each wrench part is finished.

The wrench parts that are carried as a set by the fixture must be clamped in substantially identical positions in their respective planes so that the finished parts will be interchangeable. Dimensional variations may occur between any one and the others of a set particularly where the workpieces are forged and a problem arises of clamping each workpiece with the same amount of force and in the same relative positional relationship. As the pair of movable jaws seat to clamp the wrench parts it may occur that the wrench part on one side of a movable jaw is slightly larger than the wrench part on the other side of the same jaw. The result that one part may be clamped more tightly and in a different relative position than the other is eliminated in accordance with a feature of the present invention wherewith the actuating means for the pair of movable jaws permit them to seat equally and uniformly on the set of Wrench parts irrespective of dimensional variations that may occur.

Such means for actuating the pair of movable jaws includes connecting structure which moves them in unison each between a pair of stationary jaws and so that each is capable of seating slightly oif center with relation to its respective pair of stationary jaws. The connecting structure of the movable jaw actuating means connects the pair of movable jaws together and to the stationary structure of the base 31 as shown best in the horizontal view of Fig. 5 and the related vertical sectional views of Figs. 3 and 4. As hereinbefore described the movable jaws 41L and 41R are individually secured to the jaw support members 471.. and 47R which are integral with the vertical rods 49L and 49R respectively. The lower ends of the rods 49L and 49R are connected together by a common bar 79 which is horizontally disposed and extends longitudinally within a hollow cavity 81 which is formed in the lower part of and opens to the bottom of the base 31. The lower ends of the rods 49L and 49R are each reduced in diameter and their reduced portions extend through a pair of vertical openings 83 (Fig. 5) formed in the common bar 79 adjacent its ends with ample clearance, the extremities of the reduced-portions projecting beneath the bar 79 and being threaded to receive suitable fasteners 85 (Fig. 3) which each retains a pair of washers 87 against the underside of the bar 79, the latter being urged downwardly at its ends by the connection to be described at its center. The pairs of washers 87 have mating faces which are double convexly, preferably spherically, curved to facilitate relative sliding therebetween and to permit rocking movement between the bar "79 and the rods 49L and 49R, the fulcrum of rocking for each rod being on the underside of the bar '79. When it is desired to substitute a different pair of movable jaws for use with a different workpiece size, a different set of jaw support members 47L and 47R and integral rods 49L and 49R are employed. Substitution is accomplished by simply disconnecting the lower ends of the rods 49L and 49R from the bar 79 and a different set of jaw support members and integral rods corresponding to the substituted pair of movable jaws are aifixed to the bar 79.

The bar 79 extends longitudinally beneath the stationary center jaw 38 and therebelow at its center it is connected to the lower end of a shaft 89 as shown in Fig. 4. For this purpose the bar 79 is provided with a central vertical opening 91 which is oversize in relation to the portion of the shaft 89 which extends therethrough and above the said portion of the shaft and the bar 79 an integral flange 93 is formed which is larger than the opening 91. A pair of washers 95 similar to the washer pairs 37 previously mentioned are retained between the flange 93 and the top side of the bar 79, the latter being urged upwardly at its center by the connections mentioned at its ends with the rods 49].. and 49R. Thus the common bar 79 is able to rock at its center about the shaft 83, the fulcrum of rocking being on the top side of the bar.

The lower extremity of the shaft 85 is threaded to re ceive a fastener 97 and the center of the shaft is also threaded to engage a sleeve nut 99 secured to the base 31 by suitable means such as the bolt shown and indicated at 103 in Fig. 4. The sleeve nut 99 is fitted in an upright passageway 101 which opens from below to the cavity 81 and extends through the center post 35. The passageway 181 is aligned with an opening 105 formed in the center of the jaw 33 through which the upper end of the shaft 83 extends so as to be accessible from above the fixture and enclosed by structure, as at Hi7 (Fig. 4) which is integral with and upstands from the jaw 38 near its center. The upper end of the shaft is suitably formed for engagement with a wrench by which it may be rotated to raise or lower the common bar 79. Movement of the common bar 79 carries with it the rods 49L and 49R and so raises or lowers the movable jaws 41L and 4iR as desired to clamp the set of wrench parts 11 in place on the fixture.

in operation of the fixture of the present invention when it is desired to clamp a set of wrench parts of a given size the pins 59 are placed in their respective openings 63 each of which corresponds to the particular size of the wrench parts to be clamped and the proper side of fixture jaws is selected. The movable jaws are first raised above their respective stationary jaw pairs and the lower ends of the wrench parts are placed over their re spective pins 59 by way of their openings 14 and rotated so that their heads are disposed against the inner faces of the stationary end jaws 37L and 37R and the opposite faces of the stationary center jaw 33. The wrench parts are temporarily held in the desired positions until the pair of movable jaws 41L and 41R are actuated to seat against the heads of the wrench parts by movement of the bar 79 upon rotation of the shaft 39. As the movable jaws 41L and 41R are commonly actuated between their respective stationary jaw pairs they are each capable of off center movement as mentioned to compensate for dimensional variations in the two wrench parts between which each movable jaw seats. Precise adjustment of the relative positions of the heads of the wrench parts is made before the shaft S9 is finally tightened and before the fixture is placed on a pallet to be transported through the requisite number and types of tool stations which are required to finish the wrench parts. The wrench parts are thus securely clamped and maintained throughout the entire machining operations in the proper positional relationship with respect to the required tools so that uniform workparts are consistently produced with a minimum of cost and elimination of scrappage of parts.

It will thus be seen that there has been provided by the present invention a work handling fixture by which the objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. It will be apparent that the invention is susceptible to modification, variation and change without departing from the spirit thereof or from the scope of the appended claims.

What is claimed is:

l. A work-holding fixture for maintaining a plurality of substantially like workpieces in predetermined positions while metal working operations are performed thereon comprising a base, a plurality of stationary jaws fixedly secured in spaced relation on the base, including a pair of end jaws and a center jaw disposed between the pair of end jaws, and a pair of movable jaws each positioned between a pair of said stationary jaws which consists of said center jaw and one of said end jaws and spaced therefrom so that a pair of workpieces may be clamped between each of the movable jaws and its respective pair of stationary jaws with each workpiece being wedged between a pair of opposed faces, one of which is on one of the stationary jaws and the other of which is an adjacent face of one of the movable jaws, all of said jaws being constructed so that each said pair of opposed faces relatively converge toward a vertical plane, a pair of rods slidably carried in the base and having their upper ends individually and removably secured to the pair of movable jaws, a common bar extending longitudinally of the base and connecting together adjacent its ends the lower ends of the pair of rods, means connecting the common bar at its center to the base and including an adjustable member threadably secured in the base, adjustment of said member actuating said common bar to commonly move the pair of movable jaws each between its respective pair of stationary jaws and each essentially in one plane so that the amount of relative convergence between the pairs of opposed faces increases whereby to seat and clamp each of the pair of movable jaws against its respective pair of workpieces to secure them in place on the fixture in predetermined positions, means permitting rocking movement between the pair of rods and the common bar and permitting the common bar to rock at its center thereby permitting slight off-center movement with respect to each said one plane of each of the movable jaws so that its respective pair of workpieces are clamped in substantially identical positions in their respective planes in spite of slight dimensional variations therein.

2. A work-holding fixture as defined in claim 1 wherein the common bar is urged downwardly at its ends by the connection at its center and is urged upwardly at its center by the connection at its ends, and wherein the fulcrum of rocking movement of each rod is on the underside of the bar and the fulcrum of rocking movement of the common bar is at its center on its topside.

3. A work-holding fixture as defined in claim 2 where in the connection between each rod and the common bar includes a pair of washers which are retained against the underside of said bar and which have double convexly curved mating faces and wherein the connection between said member and the common bar includes a pair of washers which are retained against the topside of said bar and which also have double convexly curved mating faces.

4. A work-holding fixture for maintaining a common end of each of a plurality of elongated forgings in predetermined positions while metal working operations are performed thereon comprising a base, a plurality of stationary jaws fixedly secured in spaced relation on the base including a pair of end jaws and a center jaw disposed between the pair of end jaws, and a pair of movable jaws each positioned between a pair of said stationary 8 jaws which consists of said center jaw and one of said end jaws and spaced therefrom so that a pair of forgings may be clamped between each of the movable jaws and its respective pair of stationary jaws with a common end of each forging being wedged between a pair of opposed faces, one of which is on one of the stationary jaws and the other of which is an adjacent face of one of the movable jaws, all of said jaws being constructed so that each said pair of opposed faces relatively converge toward a vertical plane, a pair of rods slidably carried in the base and having their upper ends individually and removably secured to the pair of movable jaws, a common bar extending longitudinally of the base and connecting together adjacent its ends the lower ends of the pair of rods, means c nnecting the common bar at its center to the base and including an adjustable member threadably secured in the base, adjustment of said member actuating said common bar to commonly move the pair of movable jaws each between its respective pair of stationary jaws and each essentially in one plane so that the amount of relative convergence between the pairs of opposed faces increases whereby to seat and clamp each of the pair of movable jaws against its respective pair of forgings to secure their common ends in place on the fixture in predetermined positions, means for pivotally supporting the other end of each forging in selectively adjustable positions relative to said jaws to accommodate different forging sizes, means permitting rocking movement between the pair of rods and the common bar and permitting the common bar to rock at its center thereby permitting a slight off-center movement with respect to each said one plane of each of the movable jaws so that the common ends of its respective pair of forgings are clamped in substantially identical positions in their respective planes in spite of slight dimensionalvariationstherein.

5. A work-holding fixture as defined in claim 4 wherein the common ends of the forgings including portions wedged between said pairs of opposed faces are main tained accessible to work tools and include faces which protrude from the frontal surfaces of the adjacent pairs of jaws and wherein the frontal surfaces of the jaws generally conform to the said forging faces, and wherein the frontal surfaces of the pair of movable jaws include floor portions which together define a breaching floor over which a breaching tool may travel, and wherein means are provided for guiding the broaching tool for simultaneously broaching said protruding forging faces.

6. A work-holding fixture as defined in claim 5 wherein means are provided for breaching a transverse opening in the common end of each of the forgings which cornprises a pair of broach guide members each disposed below and spaced from one of the pair of movable jaws so as to define access openings which extend longitudinally from end to end of the said movable jaws for passing a broaching tool therethrough, each of said access openings being axially aligned. with thetransverse openings in said forgings, and wherein the frontal surfaces of the pair of stationary end jaws and the stationary center jaw include floor portions which collectively define together with the top surface of said broach guide members a floor which extends longitudinally from one end to the other of the fixture through said access openings below the-pair of movable jaws and over which a breaching tool may pass repeatedly as required to finish broaoh each of said transverse openings.

7 A work-holding fixture as defined in claim 6 wherein longitudinally extending integral rib members are formed individually on the stationary jaws and on the pair of broach guide members which stand upright from the floor portions and top surfaces thereof respectively and which are axially aligned and disposed in the same plane to'serve as guides for the breaching tool which breaches said transverse openings.

8; A work-holding fixture as defined in claim? wherein the pair of stationary end jaws are secured on the base 9 individually on a pair of outwardly protruding upright end posts and the stationary center jaw is secured on the base on an outwardly protruding upright center post, and wherein the means for pivotally supporting the opposite ends of the forgings from said common ends is adapted to accommodate different forging sizes and includes a plurality of openings which extend inwardly from opposite sides of the center post and from the inner side of each of the end posts, the openings in each post side being disposed in spaced relation to each other and with respect to said jaws each closer than the one below, and a pin corresponding to each post side interchangeably and removably secured in one of the openings on its respective post side, each of said one openings in which a pin is disposed corresponding to a given size for the set of forgings which are clamped.

References Cited in the file of this patent UNITED STATES PATENTS 620,495 Ramseaur Feb. 28, 1899 834,481 Mortensen Oct. 30, 1906 2,596,453 Weidel May 13, 1952 2,612,821 Skay Oct. 7, 1952 FOREIGN PATENTS 3,413 Great Britain Feb. 16, 1884 25,666 Great Britain Dec. 6, 1898 

